This invention relates to the control of mining machinery, and is particularly but not exclusively applicable to the control of longwall shearers.
Longwall shearers are sizable machines, typically 8 m-10 m long, and it is necessary for the operator to see the ends when setting the machine ready for use. It is therefore conventional to provide a control station at each end of the machine, which includes controls for a number of functions plus associated displays.
The control stations may be electrical. They must then either be flameproof, leading to high bulk, weight and manufacturing cost, or they must be "intrinsically safe" within stautory regulations, which requires rather complex and expensive interface circuitry and places constraints on physical layout. Alternatively, the control stations may be hydraulic, but this leads to complex and space-consuming hydraulic piping and maintenance is difficult in the environment of a coal mine.
None of these approaches is very satisfactory. It is therefore an object of the invention to provide a control system in a mining machine which presents no explosion risk, requires little and simple maintenance, and which is relatively simple to manufacture.